This invention relates to a storage system including several aligned pallet racks which are movable forward and backward in a direction parallel to the row of racks so as to form a passageway between two selected racks situated adjacent to one another. In this type of system, a carriage is arranged for depositing and removing articles in pallets, the carriage having at least one fork lift. The fork lift can be raised and lowered, and is movable horizontally forward and backward. The carriage can be moved between a position outside the passageway and the selected position in the passageway, the outside position preferably being on a transfer carriage movable along the row of racks to a selected passageway.
Compact storage structures in which racks supported by wheels and having shelves are placed in a row, and are movable to form a passageway between two selected adjacent racks, are well known. These racks are either manually movable or each rack can for example have an electric reversible motor for moving the rack in the desired direction. The control of the movement of the racks can be more or less automatic.
The principles of compact storing in connection with storage systems of shelf racks are nowadays employed also for pallet racks. Thus, several double racks, i.e. two single racks placed with their backs facing one another, are disposed in a row beside each other so that the racks are normally close together, space being provided for one passageway to exist somewhere between two racks. This enables the rack locations on either side of the passageway to be accessible. Manually controlled, electrically operated fork trucks have been used to deposit and remove articles in this type of system. A disadvantage with trucks of this type is that the passageway must be relatively broad so that the truck can be turned through 90.degree. when articles are to be placed in or taken out of the racks. Another disadvantage of such systems is that guide rails for the trucks are required in certain cases, for instance when the racks are used in a warehouse for storing frozen food, and it is desired to substitute an automatically operated truck for a manually operated truck. These additional guide rails will inconveniently cross the rails normally arranged in the floor to guide the movement of the racks. Furthermore, when employing manually operated trucks it is necessary to place the guide rails for the movement of the racks below the floor surface to permit unimpeded movement of the truck into and out of the passageway.